/*===========================================================================

 Copyright (C) 2007-2020 Yves Renard, Julien Pommier.

 This file is a part of GetFEM++

 GetFEM++  is  free software;  you  can  redistribute  it  and/or modify it
 under  the  terms  of the  GNU  Lesser General Public License as published
 by  the  Free Software Foundation;  either version 3 of the License,  or
 (at your option) any later version along with the GCC Runtime Library
 Exception either version 3.1 or (at your option) any later version.
 This program  is  distributed  in  the  hope  that it will be useful,  but
 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 or  FITNESS  FOR  A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 License and GCC Runtime Library Exception for more details.
 You  should  have received a copy of the GNU Lesser General Public License
 along  with  this program;  if not, write to the Free Software Foundation,
 Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA.

===========================================================================*/
#include "getfem/bgeot_kdtree.h"
#include "getfem/bgeot_kdtree.h"
#include "getfem/dal_bit_vector.h"
using std::endl; using std::cout; using std::cerr;
using std::ends; using std::cin;
using bgeot::base_node;
using bgeot::size_type;
using bgeot::dim_type;

bool quick = false;

void brute_force_points_in_box(const std::vector<base_node>& v, 
			       dal::bit_vector& ipts,
			       const base_node &bmin, 
			       const base_node &bmax) {
  ipts.clear();
  for (size_type i=0; i < v.size(); ++i) {
    bool is_in = true;
    for (size_type k=0; k < bmin.size(); ++k) {
      if (v[i].at(k) < bmin[k] || v[i].at(k) > bmax[k]) { is_in = false; break; }
    }
    if (is_in) ipts.add(i);
  }
}

void verify_points_in_box(const std::vector<base_node>& v, bgeot::kdtree& tree, 
			  const base_node &bmin, 
			  const base_node &bmax) {
  dal::bit_vector bv1, bv2;
  //cout << "verify_points_in_box : " << bmin << "," << bmax << "\n";
  brute_force_points_in_box(v,bv1,bmin,bmax);
  bgeot::kdtree_tab_type ipts;
  tree.points_in_box(ipts,bmin,bmax);
  for (size_type i=0; i < ipts.size(); ++i) bv2.add(ipts[i].i);
  if (bv1 != bv2) {
    cout << "verify_points_in_box: error, brute force gave points\n " << bv1 << ",\nwhile points_in_box returned : " << bv2 << "\n";
  } else { cout << "."; cout.flush(); }
  assert(bv1 == bv2);
}

void check_tree() {
  bgeot::kdtree tree;
  std::vector<size_type> ipts;
  std::vector<base_node> pts;
  base_node one(2); gmm::fill(one, 1);
  pts.push_back(base_node(.4,.7));
  pts.push_back(base_node(1.4,.8));
  pts.push_back(base_node(2.4,.3));
  pts.push_back(base_node(3.4,.1));
  pts.push_back(base_node(.5,2.2));
  pts.push_back(base_node(-.8,.4));

  for (size_type i=0; i < 50; ++i) pts.push_back(base_node(gmm::random(),gmm::random()));
  for (size_type i=0; i < pts.size(); ++i) tree.add_point(pts[i]);
/* all points */
  verify_points_in_box(pts, tree, base_node(0.,0.),base_node(6.,6.));
  
  /* point search */
  for (size_type i=0; i < pts.size(); ++i) {
    for (size_type j = 0; j < 2; ++j) {
      base_node bmin = pts[i], bmax = pts[i];
      if (j == 0) { bmin -= 1e-5 * one; bmax += 1e-5 * one; }
      verify_points_in_box(pts, tree, bmin, bmax);
    }
  }

  /* check special cases (all points the same, all points on same plane etc) */
  for (size_type repeat=0; repeat < 200; ++repeat) {
    pts.clear(); tree.clear();
    double pval[3] = { 0.3, 24.0, -2.3 };
    bool sameplane[3];
    for (size_type i=0; i < 3; ++i) sameplane[i] = ((rand() % 3) == 0);
    for (size_type i=0; i < 200; ++i) {
      base_node pt(3);
      for (size_type k=0; k < pt.size(); ++k) { 
	if (sameplane[k]) pt[k] = pval[1]; else pt[k] = pval[rand()%3]; 
      }
      pts.push_back(pt);
      tree.add_point(pt);
    }
    verify_points_in_box(pts, tree, base_node(-100.,-100.,-100.),base_node(100.,100.,100.));
    verify_points_in_box(pts, tree, base_node(-100.,-100.,-100.),base_node(0.,0.,0.));
    verify_points_in_box(pts, tree, pts[0], pts[0]);
    verify_points_in_box(pts, tree, pts[0], pts[1]);
  }
  cout << "\nthe kdtree is ok!\n";
}

void speed_test(unsigned N, unsigned NPT, unsigned nrepeat) {
  bgeot::kdtree tree;
  base_node pt(N);
  cout << "speed test for the kdtree\n";
  double t = gmm::uclock_sec();
  for (size_type i=0; i < NPT; ++i) {
    for (dim_type k = 0; k < N; ++k) 
      pt[k] = gmm::random(double())*2.;
    tree.add_point(pt);
    assert(pt.refcnt()>1);
  }
  t = gmm::uclock_sec();
  cout << "point list built in " << gmm::uclock_sec() - t << " seconds.\n";
  bgeot::kdtree_tab_type ipts;
  tree.points_in_box(ipts,pt,pt);
  cout << "tree built in " << gmm::uclock_sec() - t << " seconds.\n";
  bgeot::base_node bmin(0.25,0.25,0.4), bmax(0.5,0.5,3.3);
  size_type npt=0;
  t = gmm::uclock_sec();
  for (size_type c=0; c < nrepeat; ++c) {
    tree.points_in_box(ipts,bmin, bmax);
    npt = ipts.size();
  }
  cout << "BOX QUERY: nb points in " << bmin << ":" << bmax << " is : " << npt << "\n";
  cout << "average query time is: " << (gmm::uclock_sec()-t)/nrepeat*1e6 << " microseconds\n";

  t = gmm::uclock_sec();
  for (size_type c=0; c < nrepeat*200; ++c) {
    tree.points_in_box(ipts,pt,pt);
    npt = ipts.size();
  }
  cout << "POINT QUERY: nb points in " << pt << ":" << pt << " is : " << npt << "\n";
  cout << "average query time is: " << (gmm::uclock_sec()-t)/(nrepeat*200.)*1e6 << " microseconds\n";
}

int main(int argc, char **argv) {
  if (argc == 2 && strcmp(argv[1],"-quick")==0) quick = true;
  check_tree();
  if (!quick)
    speed_test(3,300000,20000);
  else speed_test(2,10000,100);
  return 0;
}
